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采用电阻炉对轧制后的5A02合金薄壁管材进行了均匀化退火,利用光学显微镜、硬度计和万能试验机分析了退火制度对5A02合金薄壁管材组织与性能的影响。研究结果表明:当退火温度较低时,保温60min后的合金组织中仍然存在一定量的纤维状组织,当退火温度升高到410℃时,保温30min后管材中的纤维状组织已完全消失,再结晶组织较细小;随着退火温度的升高和保温时间的延长,退火后管材的强度、硬度逐渐降低,伸长率逐渐升高,但保温时间大于30min的性能变化不大;退火温度较低时,试样断口中韧性断裂特征比较明显,但是仍存在少量剪切变形的特征,随着退火温度的升高,合金断口呈出现大量韧性断裂的韧窝组织,没有剪切变形的特征;最终确定了均匀化退火制度为410～430℃,保温时间为30～60min,抗拉强度和伸长率都满足了用户指标的要求。
The annealing furnace was used to homogenize annealed 5A02 thin-walled pipe. The microstructure and properties of 5A02 thin-walled pipe were analyzed by optical microscope, hardness tester and universal testing machine. The results show that when the annealing temperature is low, a certain amount of fibrous structure still exists in the alloy after 60min incubation. When the annealing temperature is increased to 410 ℃, the fibrous structure in the pipe disappears completely after 30min incubation, The recrystallized microstructure is smaller; with the increase of annealing temperature and holding time, the strength and hardness of the annealed pipe gradually decrease, while the elongation increases gradually. However, the annealing temperature is less than 30min. However, there is still a small amount of shear deformation. With the increase of annealing temperature, a large amount of tough ductile dimples appear in the fracture surface of the alloy without shear deformation. Finally, the homogenization annealing system was determined to be 410 ~ 430 ℃, and the holding time was 30 ~ 60min. The tensile strength and elongation all satisfied the requirements of user’s index.